Enterprise data centers may provide services to users through a server cluster approach. A server cluster may include a plurality of physical servers or virtual servers to provide the same service, for example, such as web access service. A load balance device (LBD) is deployed at the front end of a cluster. According to a predetermined load balancing algorithm, the LBD may distribute access requests initiated from external hosts to different servers in a server cluster for further processing, and then the LBD sends responses returned from the servers to the external host.